Expert Guide : Food for Saltwater fish

Feeding saltwater fish in aquariums can be more complicated than freshwater. With the vast majority of fish coming from the wild collection and many species having a specialized diet, it is more than ever necessary to understand how these fish feed and the best types and variety of foods. This article will explore in detail food for saltwater fish in home aquariums.


Types of Saltwater Fish Food

When feeding saltwater fish, you must carefully observe the fish when feeding and exploring the different foods available. This is the best way to ensure that our saltwater fish receive the nutrients within a balanced diet.

Saltwater fish have (often extremely) specific dietary needs, so feeding them correctly can be a lot of work. Offering a variety of foods and seeing which fish prefer is the safest way.

With the increasing advent of technology and research applied to the maintenance of saltwater fish in aquariums, it is possible to find an increasing variety of different types of food. As with freshwater fish, the main options on the market are pellets and flakes, frozen and freeze-dried foods, and live and fresh foods.


Pelleted and Flake Foods

Commercial dry feeds such as pellets and flakes are the first choice for feeding saltwater fish. Scientists formulate these foods complexly to meet the basic fish needs. 

These foods are in different categories, like food for carnivorous, herbivorous, and omnivorous fish. The problem is that, in addition to the high food specificity, with the still low number of research linked to the nutrition of reef fish, these foods are not always enough to meet the animals’ needs. Many fish do not accept commercial foods and can quickly perish in aquariums (such as the copper band butterfly).

Marine herbivorous fish have algae as a large part of their diet. Algae provides an incredible amount of nutrients, pigments, and fiber. Commercial formulations seek to contain these ingredients, coming close to the diet of fish in nature. Algae such as chlorella and spirulina are common ingredients in these foods.

For carnivorous fish, the formulations are animal-origin ingredients based, containing fish meal, krill, shrimp, copepods, and other invertebrates. Carnivores do not need as much fiber in their diet, meaning these pellets and flakes provide perfect amounts of high-quality protein and essential fatty acids such as Omega 3.

For omnivores, the food contains a range of ingredients of both plant and animal origin.

It’s worth mentioning that although commercial dry food should be the basis of the diet of saltwater fish, you should not use only this food. Other types of food (and more than one label) are essential to keep fish healthy and active.


Frozen and Freeze-Dried Foods

Frozen and freeze-dried foods are great companions for marine aquarists. The supply of these foods considerably increases the quality of the fish’s diet. This is because in addition to providing foods close to those found in nature, adding diversity to the diet helps to break the monotony and replace nutrients that the fish needs.

Frozen shrimp, shellfish (mussels, squid, octopus), mysis, and other invertebrates are highly effective foods to serve herbivorous and carnivorous fish. These ingredients are essential in the diet of some species that do not survive (or have health problems) when kept only on dry food, such as many puffer fish.

Because they can be partitioned and frozen in portions, they become an easy-to-use alternative, being very convenient to avoid contamination due to handling. When using these foods, they must be fresh, clean, and previously frozen.


Live Foods

Live foods are a component in the diet of saltwater fish, but in addition to most of them being small in size, they can be hard to find in your region. Plankton (zoo and phyto), amphipods, rotifers, brine shrimp, and copepods are the most common in stores and are used to feed small fish or those with small mouths, which is common in many reef fish.

Using live food is a good way to keep your fish active and interested, as they have to hunt for food, stimulating instincts.

For large carnivore fish, such as groupers, live fish can be used, with mollies being a common choice for feeding fish. Mollies are fish that survive in water with high salinity.

When using live food, it is essential to know where they come from and whether they are clean and free from contamination. The ideal is always to keep and reproduce them yourself, or at least quarantine them before offering them to your saltwater fish. This is the best way to avoid contaminating the aquarium or introducing diseases and parasites.

If you have corals and other invertebrates, they will probably also benefit from these foods. Be careful with the quantity offered; live foods can quickly degrade water quality.


Seaweed and Algae

As we mentioned previously, seaweed and even some vegetables are great additions to the diet of saltwater fish. Some fish (such as certain species of tang) feed almost exclusively on algae because it is necessary to include them in the diet. Even though they are in numerous commercial foods, their acceptability is not always high. Therefore, the best way to complement possible nutritional imbalances is to offer fresh algae such as Nori and vegetables such as napa cabbage directly in the aquarium.

Fish love these foods and there will hardly be anything left in the aquarium. Use feeding clips to hold the leaves, and remember to remove any debris left in the aquarium.


DIY Saltwater Foods

Among marine aquarists, it’s normal to use homemade foods. There are countless recipes on the internet and in books. Even though making your food for marine fish is not ideal, homemade foods do have their value.

Due to the specific nature of feeding saltwater fish, making our fish food means using quality ingredients and increasing the palatability (flavor) of the formulation, which makes the fish eat more.

DIY food should never be the basis of a fish diet. This type of food degrades water quality quickly, meaning only experienced aquarists should use it. To make it, use only fresh ingredients, such as squid, shrimp, and algae, and base yourself on specific recipes from aquarists or renowned professionals.


Nutritional Needs of Marine Fish

Different marine fish species have different nutritional needs. Even though we still don’t know much about the nutritional needs of marine ornamental fish, there is some knowledge that we can use as a basis. Saltwater fish need the same micro and macronutrients as other animals. These nutrients come from a rich and diverse diet. Each component of the diet will act in a specific way.


Essential Macronutrients and Micronutrients

When discussing macronutrients, we refer to proteins, carbohydrates, and lipids. These play an essential role in the development of marine fish.

Proteins are vital parts of fish growth, as are amino acids. These fish often metabolize carbohydrates from plant and animal foods, which are responsible for maintaining energy and the proper functioning of the balance of the fish’s organism. Fats are a source of energy and play an essential role in the proper functioning of organs and the absorption of vitamins.

Micronutrients encompass vitamins and minerals. These make it possible to maintain physiological functions and also help various organs and the immune system.


Fatty acids

Fatty acids, especially omega ones (mainly 3 and 6), are essential diet components. The fish organism does not produce them, being obtained directly from their food. Explaining their function in depth is extremely complex, and aquarists should understand that these fatty acids are of great importance in saltwater environments, acting directly on the composition of cell membranes and the immune response of fish.


The Role of Supplements and Vitamins

Even with a balanced diet, in some situations, such as after an outbreak of an illness or to speed up the recovery of a particular fish, it is necessary to offer some supplement or vitamin to saltwater fish.

The use of supplements and vitamins, ideally, should be prescribed and monitored by a saltwater fish professional and used consciously only during the prescribed period.

In stores, we find a multitude of different supplements, as well as vitamins. The most popular are certainly garlic-based supplements, used alongside feed, for medicinal purposes, and foods enriched with a high level of vitamins.


Special Dietary Needs for Specific Marine Species

As we have highlighted several times throughout this article, feeding saltwater fish can be complicated, as different species have very specific diets. In aquariums, we deal with this problem by offering the widest possible range of foods and observing which fish accept them best. Let’s explore the food preferences of some common species in marine aquariums.



Probably one of the best-known fish in the world, the clownfish is a classic in saltwater aquariums. This fish has a predominantly carnivorous diet and feeds (and grows well) on dry, live, and fresh foods without any major problems. The symbiotic relationship between these fish and sea anemones ends up influencing their diet, while the anemones protect them, they offer the anemones leftover food.



Lionfish are carnivorous animals, with a voracious appetite for other fish and invertebrates. Aquariums offer live food and feed to carnivorous fish. Lionfish cannot always accept dry food quickly, so live, fresh, and frozen food must be regularly offered to avoid nutritional problems.



Angelfish are a diverse group of fish, with different species and different food preferences. Many feed almost exclusively on algae, while others are carnivorous, with a large part of their diet based on invertebrates. Research the species you want to keep and its dietary needs.

Keep in mind that angels need a wide range of foods to be healthy, and they do not adapt very well to just commercial diets.


Butterfly Fish

Just like angels, butterflyfish are also a diverse group. Some are specialized in feeding on specific types of invertebrates, while others are strictly herbivores, feeding on plants among coral.

Some species, most likely due to their diet, have a short lifespan in aquariums. Therefore, it is vital to research their dietary needs and offer a diet perfect for the species in question.


Feeding Techniques and Strategies

When approaching a topic as extensive, controversial, and complex as feeding marine fish in domestic aquariums, in addition to the food itself, it is often necessary to employ some techniques and strategies so that all fish receive food adequately.


Target Feeding

Target feeding is when we offer food directly in a specific location or area of the tank. This technique is used when we have fish that live in holes or holes, as well as being useful to reduce competition or offer some specific type of food to a particular fish.

For this purpose, use pipettes, syringes, or pipes to deliver the food to the desired location.


Broadcast Feeding

Broadcast, or dispersion feeding, is when we distribute food throughout the aquarium, allowing the fish to exhibit foraging behavior, something close to what they would do in a natural environment. Liquid-based live foods are used through a cup or even a pipette. When using this method, it is vital to be aware of overfeeding, which can degrade water quality. The corals and invertebrates in the tank also benefit from this type of feeding.


Feeding Stations and Tools

Feeding stations are objects (generally floating) used to delimit an aquarium area. In this location, we will deposit the food. The station will act as a physical barrier, concentrating all the food in that region.

Several tools are available to saltwater aquarists to help feed fish, such as tweezers and large pipettes. These tools are valuable when offering food in a specific way, increasing efficiency and reducing waste.


Alternate Eating Schedules

Alternating feeding times in the aquarium is a strategy for introducing animal welfare and getting the fish out of their routine. In addition to changing the schedule, alternate the types of food between meals.



Feeding saltwater fish is still a bit nebulous from a scientific point of view and incredibly alters the fish lifespan in our aquariums. Offering a variety of foods and ensuring that all the fish are eating is vital to ensuring the good health of the tank and the longevity of the animals.

Through reading and research, we can meet the unique nutritional and dietary needs of the many ornamental species of saltwater fish. There are a variety of types of food available to aquarists, who must invest time and effort in the proper nutrition of their fish. For this, we have some strategies, such as using tools and feeding the aquarium differently.

Did you already know that varying your fish’s feeding time is a great strategy for improving their feeding time? Share with us your experiences in the world of aquarium farming, through the exchange of information we build a better hobby.